stdlib organization & documentation improvements (#20971)

* stdlib organization & documentation improvements

* fix CI

* Update doc/lib.md

Co-authored-by: Juan Carlos <juancarlospaco@gmail.com>

* fix ci, remove jshttpcore, export in jsfetch instead

* fix alphabetical order violations

* add cmdline, db_odbc

Co-authored-by: Juan Carlos <juancarlospaco@gmail.com>

lib/deprecated/pure/mersenne.nim

@@ -0,0 +1,51 @@
+#
+#
+#            Nim's Runtime Library
+#        (c) Copyright 2015 Nim Contributors
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+## The [Mersenne Twister](https://en.wikipedia.org/wiki/Mersenne_Twister)
+## random number generator.
+## .. note:: The procs in this module work at compile-time.
+
+{.deprecated: "use `std/random` instead".}
+
+runnableExamples:
+  var rand = newMersenneTwister(uint32.high)  ## must be "var"
+  doAssert rand.getNum() != rand.getNum()  ## pseudorandom number
+## See also
+## ========
+## * `random module<random.html>`_ for Nim's standard random number generator
+type
+  MersenneTwister* = object
+    ## The Mersenne Twister.
+    mt: array[0..623, uint32]
+    index: int
+
+proc newMersenneTwister*(seed: uint32): MersenneTwister =
+  ## Creates a new `MersenneTwister` with seed `seed`.
+  result.index = 0
+  result.mt[0] = seed
+  for i in 1'u32 .. 623'u32:
+    result.mt[i] = (0x6c078965'u32 * (result.mt[i-1] xor
+                                      (result.mt[i-1] shr 30'u32)) + i)
+
+proc generateNumbers(m: var MersenneTwister) =
+
+  for i in 0..623:
+    var y = (m.mt[i] and 0x80000000'u32) +
+            (m.mt[(i+1) mod 624] and 0x7fffffff'u32)
+    m.mt[i] = m.mt[(i+397) mod 624] xor uint32(y shr 1'u32)
+    if (y mod 2'u32) != 0:
+      m.mt[i] = m.mt[i] xor 0x9908b0df'u32
+
+proc getNum*(m: var MersenneTwister): uint32 =
+  ## Returns the next pseudorandom `uint32`.
+  if m.index == 0:
+    generateNumbers(m)
+  result = m.mt[m.index]
+  m.index = (m.index + 1) mod m.mt.len
+  result = result xor (result shr 11'u32)
+  result = result xor ((result shl 7'u32) and 0x9d2c5680'u32)
+  result = result xor ((result shl 15'u32) and 0xefc60000'u32)
+  result = result xor (result shr 18'u32)